Electrically-heated culinary apparatus.



W. S. HADAWAY, JR. & E. E. ROSE. ELEOTRIGALLY HEATED CULINARY APPARATUS.

APPLICATION FILED OUT 8, 1910.

Patented June 4, 1912.

ATTORNEY UNITED STATES PATENT OFFICE.

WILLIAM S. HADAWAY, JR., 0F

OF PITTSBURGH, PENNSYLVANIA, ASSIGNORS EAST ORANGE, NEW JERSEY, ANDEDWARD E. ROSE,

TO WESTINGHOUSE ELECTRIC &

MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ELECTRICALLY-HEATED CULINARY APPARATUS.

Specification of Letters Patent.

Patented June 4, 1912.

Application filed October 8, 1910. Serial No. 586,081.

The object of our invention is to provide a device of theabove-mentioned character which shall be simple and durable inconstruction and eflicient in operation.

It is well known in the art that the efliciency and the life of a heaterunit are greatly increased by subjecting it to pressure, and ourinvention embodies simple and inexpensive meansfor obtaining the desiredconditions.

In the accompanying drawing, Figure 1 is a view, partially in elevationand partially in section, Fig. 2 is a plan view, with a portion brokenaway, and Fig. 3 is a seetional View, on the plane IIIIII of Fig. 1, ofa device constructed in accordance with our invention. Figs. 4: and 5illustrate two steps in the process of seaming the outer and innershells together, whereby a pressure upon the heater element is secured,as hereinafter described, and Fig. 6 is a sectional view of a modifiedform of heater unit.

Referring to the drawings in detail, the device comprises, essentially,an inner receptacle or shell 1, of thin heat-conducting material, anouter shell 2 which is also formed of thin heat-conducting material andis adapted to fit tightly over the inner shell, a circular band 3 whichsurrounds the upper portion of the inner shell, and a heater unit 4,which is assembled between the bottom' walls of the aforesaid shellmembers and is maintained under pressure.

The inner shell 1 is, in general, of cylindrical shape, the upper rim ofwhich is turned over, to form a double seam 6 with the upper edge of thecircular band 3, in order to securely fasten the two members together.The outer shell 2 is substantially of the same form as the inner shell,and is adapted to fit tightly over it. A channel or recess 8 is providedin one side of the,

outer shell 2 to accommodate the leads to the heater umt 4', and theouter shell is also provided with a suitable bracket 9 upon which aplurality of plug terminals 10 and 11 are mounted.

The heater unit 4 may be of any suitable construction, but preferablycomprises a slotted resistance ribbon 14:, wound into a flattened helixabout an insulating disk 15 which is provided with notches 16 to holdthe ribbon in position. Inasmuch as the arrangement and structure of theresistance ribbon are shown and described in detail in Patent No.890,856, granted, June 16, 1908, to the Hadaway Electric Heating &Engineering Company, a further description is not considered necessary.

'Ribbon connections or leads 17 and 18 are connected to the heater unit4 and extend up through the recess 8 in the outer shell to theplugterminals 10 and 11, said leads being suitably insulated from eachother and from the adjacent walls by means of strips of insulation 19.

In assembling the heater unit, insulating disks 21 and 22 are placedupon the respective sides of said unit to separate the resistance ribbon14 from the containing vessel. Pressure plates or disks 23 and 24 arealso placed upon the respective sides of the heater unit, in order toreinforce and lend rigidity to the thin bottom walls 25 and 26 of theouter and inner shells,re-

spectively.' Having assembled the heater unit and the insulating disksand pressure plates, the upper edge 27 of the outer shell 2 and thelower edge 28 of the circular band 3 are seamed together in such manneras to secure and maintain a considerable pressure upon the heater unit.

In some instances, it may be expedient to assemble the component partsof the heater into an incased, self-contained unit, as shown in Fig. 6,in order to hold the parts together and provide a single structure whichwould materially facilitate the preliminary handling and treatment ofthe heater unit before it is associated with the containing vessel.Referring particularly to .Fig. 6, itwill be observed that theresistance ribbon 14 and the insulating disks 15, 21 and 22 areassembled as hereinbefore described. Furthermore, an incasing sheath 29is provided which envelops these parts and thus forms a simple andself-contained 'unit. The incasing sheath 29 is preferably constructedof aluminum or sheet copper, although any suitable material may, ofcourse, be employed.

In order to set forth more clearly the method of seaming the outer shelland circular band together, whereby a pressure is exerted upon theheater unit, attention is directed to Figs. 4 and 5, which show twosteps in the seaming process. Before assembling any of the parts of thedevice, the lower edge 28 of the circular band 3 is turned out atsubstantially right angles and the upper edge 27 of the outer shell issimilarly turned back, but in a less degree, as shown in Fig.4. Thecircular band 3 and inner shell 1 are then secured together at the topby the seam 6, as previously noted; the

heater unit 4 is assembled and placed in position wit-h the insulatingdisks 21 and 22 and the pressure plates 23 and 24, in the bottom of theouter shell 2; the ribbon connections 17' and 18 are disposed within therecess 8 and the inner shell 1 is placed in position.

If the incased type of heater, such as shown in Fig. 6, be employed, itmay be assembled as a single unit between the pressure plates 23 and 24in the bottom of the shell 2. Moreover, if desirable, said pressureplates may be suitably secured together on opposite sides of thesheathed heater unit, in such manner as to effect some initial pressureon the heater element before it is placed in position and is subjectedto the'final pressure by means of the seaming process. Having assembledthe heater, as a whole or in parts, pressure is then applied to theupper edge 6 of-the inner shell 1 and a the two shells are forcedtogether, thereby causing the edges 27 and 28 of the outer shell andcircular band, respectively, to take the positions shown in Fig. 4. Withthe pressure still applied, the extremity of the upper edge 27vof theouter shell is turned.

over the projecting edge 28 of the circular band, as shown in Fig. 5.The final step in the process consists in forcing up the seam,

now partially formed, into'engagement with the ClICtllELP- band, wherebya tension in the outer'shell is produced and a drawing 1 actioneffected, which exerts and maintains a considerable pressure upon theheater element, as will berea-dily understood. If desired, the. seam maythen be brazed inorder to form a particularly rugged andv durable Istructure. Furthermore, those skilled in the art will readily'understandthat the-heater unit 4 may be so constructed that either the whole orapart thereof maybe disposed between the side walls of the outer andinner shells, instead of being located entirely in termediate the bottomwalls, as hereinbefore shown and described.

I Although we have shown and described our device as equipped with asingle heater unit and as adapted for but a single heat, it is evidentthat a plurality of heater units may be similarly assembled and that twoor more heats may be readily obtained, if desired.

It will, of course, be understood that the device shown and described isonlyillustrative of a specific application of our invention to culinaryapparatus and thatour in vention may be readily adapted to othercommercial devices.

Modifications of thedevice shown may be effected without departing fromthe spirit and scope of our invention, and such modifications areintended to be covered by the appended claims. x

We claim as our invention:

1. The combination with an inner receptacle/of relatively thinheat-conducting material, a two part outer shell of substantially thesame form and adapted to surround said receptacle, of a suitable heaterunit and insulation therefor disposed between said receptacle and saidshell, the adjacent edges of the parts of said outer shell being foldedtogether to exert pressure upon the heater unit.

thin heat-conducting shells, the one fitted within the other, aninsulated heater unit assembled between the bottom walls of said shells,and means for maintaining a pressure on said heater unit, of rigidpressureplates or disks disposed on the respective sides of said heaterunit to reinforce the relatively flexible bottom walls of said shells.

3. A vessel comprising outer and inner shells having their edges foldedtogether and aheater element disposed between the walls of said shells,the side wall of the outer shell comprising two parts that are seamedtogether in such manner as to exert a: pressure 011' the heater element.

4. The combination with two similarly shaped receptacles, the one fittedwithin the other, of heater elements in the form of insulated flattenedhelices disposed between the bottom walls of said receptacles andmaintained under pressure by a double seam 2. The combination with tworelatively I which draws and secures said receptacles together.

5.2 vessel comprising ,two shells or receptacles of substantially thesame form, fitted the one within the other and secured together by aseam, and a heater unit or resistance. ribbon in the form of aninsulated flattened helix maintained under pressure between the bottomwalls of said shells, a

narrow space or recess being provided be-' tween the side walls of saidshells in which the heater connections are disposed and the outer shellbeing provided with suitable circuit terminals.

6. A vessel comprising an inner receptacle of relatively thinheat-conducting material, an annular band of sheet metal surrounding theupper portion of said receptacle and secured to it at its upper edge, anouter shell of materially less depth which fits closely about saidreceptacle and is provided with suitable circuit terminals, and a heaterunit comprising a strip of resistance ribbon wound about a notchedinsulating disk in the form of a flattened helix and suitable insulationtherefor disposed between the bottom walls of said receptacle and saidouter shell, the heater connections extending to the circuit terminalsin 'a recess provided between the side walls of the inner receptacle andthe outer shell, and said heater unit being subjected to pressure by thedrawing action of a double seam which secures said annular band and saidouter shell together.

7. A vessel comprising an inner receptacle, an outer shell, and aninsulated heater unit disposed between said receptacle and said shell,the peripheral wall of said shell having a fold to exert pressure uponthe insulated heater unit. 8. A vessel comprising outer and inner shellsand a heater element disposed between the bottom walls of said shells,the side wall of the outer shell being provided with a folded and brazedseam to exert a pressure upon the heater element. 7

9. The combination with a self-contained heater unit comprising aresistance element, insulation therefor, an enveloping sheath to holdsaid element and insulation together, and pressure plates disposed onthe respective sides of said enveloping sheath and secured together toproduce a slight initial pressure upon said resistance element, of aninner shell and an outer shell between the bottom walls of which saidheater unit is located, said shell embodying peripherally disposed meansfor compressing said heater unit between said bottom walls.

In testimony whereof, we have hereunto subscribed our names this 30thday of Sept,

WILLIAM S. HADAWAY, J R. EDWARD E. ROSE.

Witnesses:

ISABEL C. TERRY, B. B. HINES.

